Researchers from China's Beijing Institute of Technology developed graphene-based springs that can function as actuators. Those springs are very light and offer good thermal and electrical conductivity. They are also easy to functionalize and work in harsh conditions.
Most springs today are metal. There has been attempts to create carbon-based springs which are lightweight compared to the metal springs - but those exhibit poor elasticity. But these new graphene springs are very elastic - they can be elongated to 480% of their original size and maintain stable elasticity even after being stretched 100,000 times to 300% of their size.
To create the springs, the researchers wrapped graphene fibers around a glass bar and then annealed them at 500 degrees Celsius. Applying a voltage causes the charged loops to repel each other - which elongates the spring. functionalizing the springs with magnetic particles enables them to change in response to a magnetic field (and become magnetostrictive switches you can see this in the video in the LED demonstration).